The present disclosure relates to a refrigerator.
Refrigerators store food at a low temperature in an inner storage space closed by a door. The inner storage space can be maintained at a low temperature by continually supplying cold air thereinto. The cold air is generated by heat exchange between air and refrigerant through a cooling cycle of compression, condensation, expansion, and evaporation. The cold air supplied into the refrigerator is uniformly dispersed within the refrigerator through convection, so that food can be stored at a desired temperature in the refrigerator.
An evaporator constituting the cooling cycle is disposed in an evaporation compartment such that refrigerant exchanges heat with air circulating within the refrigerator. Since a surface temperature of the evaporator is significantly lower than an indoor temperature, while the evaporator exchanges heat with air circulating within the refrigerator, condensate water is generated on the outer surface of the evaporator. The condensate water is frozen on the evaporator or the evaporation compartment, so as to form frost. When frost is accumulated on the evaporator, heat exchange efficiency between the evaporator and inner air of the refrigerator is decreased.
To remove frost from the evaporator, a defrosting heater may be disposed at a side of the evaporator, or the cooling cycle may be reversely performed for a certain period of time, thereby melting frost formed on the evaporator. Such condensate water formed on the evaporator, or defrosted water formed by melting frost is collected in a drain pan attached to the bottom of the evaporator, and is dropped to the bottom of a machinery chamber through a drain hose.
The defrosting heater may be operated with a certain time interval, or be operated when a temperature of the evaporation compartment is equal to or lower than a specific temperature. Alternatively, whether to operate the defrosting heater may be determined according to time depending on the number of opening and closing a refrigerator door and an operation rate of the refrigerator. A defrosting sensor installed on the evaporator may sense a defrosting end time. Since such a defrosting sensor included in a typical refrigerator continuously senses a frost formation amount, power consumption is unnecessarily increased.
The defrosting sensor is disposed in a position on an evaporator where a large amount of frost is formed, and a control part starts or ends a defrosting process based on a result sensed by the defrosting sensor. In this case, the defrosting sensor cannot entirely sense the evaporator or an evaporation compartment. Thus, when the defrosting process is performed based on a result sensed by the defrosting sensor, frost formed on the evaporator or the evaporation compartment may be insufficiently removed.
In addition, the defrosting process may be performed over a defrosting time based on a result sensed by the defrosting sensor in order to ensure defrosting reliability. As a result, the power consumption is increased to operate a defrosting heater, and cooling efficiency of the refrigerator is decreased.